Expansion insert



May 13, 1952 EXPANSION INSERT Filed May 18. 1950 E. C. CROWTHER IN VEN TOR.

Patented May 13, 1952 EXPANSION INSERT b Edmond C. Crowther, Philadelphia, Pa., assignor to Illinois Tool Works, Chicago, Ill., a corpora-v tion of Illinois Application May 18, 1950, Serial No. 162,677

4 Claims. 1

This invention relates generally to expansion type inserts, and more particularly to sheet metal expansion type inserts adapted to accommodate a screw member and designed to be expanded at its entering extremity as an incident to the application of a screw member.

The present invention contemplates an expansion type insert which may be produced from sheet metal stock at minimum cost and by practicing conventional stamping and forming methods. To this end the invention proposes a sheet metal insert which may be produced fro-m a single blank of sheet metal stock.

More specifically, it is an object of the present invention to provide a sheet metal insert of the type referred to above, wherein improved means is provided at the entering extremity of a sheet metal shank to facilitate expansion of the shank as an incident to the application of a complemental screw member. The invention contemplates the employment of an expansible ring member in association with the entering extremity of a sheet metal insert.

It is a further object of the present invention to provide the above mentioned sheet metal insert, wherein the shank portion is secured against relative rotation with respect to an apertured work piece, and the inner periphery of the shank is formed with helically disposed elements designed to operatively coact with the thread helices of a complemental screw.

The foregoing and other objects and advantages will be more apparent from the following detailed description, when considered in connes-- tion with the accompanying drawing, wherein- Fig. 1 discloses an expansion type insert which is representative of one embodiment of the invention, said insert being shown in central longitudinal cross-section after it has been driven into a work aperture but prior to the insertion of a complemental screw member;

Fig. 2 is a View similar to Fig. 1 after the screw member has been applied to the sheet metal insert so as to expand the entering end thereof and thereby secure a work sheet in place;

Fig. 3 is a transverse sectional view taken substantially along the line 3--3 of Fig. 1;

Fig. 4 is a transverse sectional view taken substantially along the line 4-4 of Fig. 2;

Fig. 5 is a transverse sectional view taken substantially along the line 5 5 of Fig. 2;

Fig. 6 illustrates a blank from which the sheet metal insert disclosed in Figs. 1 to 5 may be formed; and

Fig. 7 discloses a slightly modied blank em- 2 ploying a series of indentations, as distinguished from the struck out portions illustrated in Fig. 6, for accommodating the thread helices of a complemental screw member.

Referring now tov the drawing more in detail wherein like numerals are employed to designate similar parts throughout the various figures, it will be seen that one embodiment of the present invention contemplates a sheet metal expansion type insert designated generally by the numeral I9. This fastener member I0 includes a elon gated shank portion I2 which in the present embodiment is polygonal or hexagonal in cross-section. At one extremity of the shank I2 is a head structure consisting of a plurality of radially extending tabs I4 designed to bear against the outer surface of a work sheet I 6 for the purpose of holding said work sheet against another work part such as a wooden structure I 8. The opposite extremity of the shank I2 includes an expandable section comprised of a plurality oi' circumferentially disposed inwardly bent fingers These ngers partially encircle and support a split ring or wire 22.

It is to be noted that the normal external diameter of the fastener in the vicinity of the expandable iingers 20 is approximately equal to, or slightly less than, the internal diameter of the aperture 24 in the wooden work piece I8. The shank portion I2 is also provided with struck out sections 26 which are helically distributed along and extend inwardly from the internal periphery of the shank to coact with the thread helix 28 of a complemental screw member 39.

It will be noted that when the shank I2 of the expansion insert I0 is initially inserted within the work aperture '24, the corners along the outer periphery of the shank will bite into the wall which defines the aperture 24, and thereby secure the insert against rotation within the work piece I8. Also, the opposed adjacently positioned margins of the blank from which the insert is formed, namely, the margins 32-34, Fig. 5, are adapted to bite into the wall dening the work aperture 24.

After the insert I0 has been forced'into the aperture 24, it is then in a, position to accommodate the fastening screw 30. In the drawing the work sheet I6 is apertured to accommodate the- `screw 30, and as the screw is rotatably inserted within the shank I2, the thread helices 28 thereof coact with and are guided by the helically disposed struck out elements 26. The internal diameter of the entering portion of the shank I2 is less than the external diameter of the screw thread. Thus,A as the screw approaches its nal tightening position shown in Fig. 2, the expandable entering extremity of the shank is forced radially outwardly so as to cause the resilient fingers 20 to become embedded within the work piece l=8.

In Fig. 6 a blank designated generally by the numeral 235 "is ishuwm' from whiclig-:theeinsert lili' may be formed*l That is *to say,"th'e Ymain portion" of the blank is bent to form the hexagonal shank, 10

the tabs I4 are bent radially outwardly topr vide the head section, and the fingers or.,tabs20.Y are bent inwardly to form a seat for the splitM ring 22.

In Fig. 'l a slightly inodiedlblankl(ia-isishownff- 15? This blank is similar in all respects to the blank 36 of Fig. 6 except that instead-.fof einplotiiilgli;` struck out sections, such as the sections 26, a series of indentations 26a are formed. When-the f blank Sla is formed into a-.hexagonal shank, these 20 indentation's :2 Eni, like.l the@struckzouttsections;276;-

arefdisposed*inhelicalalignmentftoaccommodate ththrea'd' helices off a .complementar screw.Y

From the foregoing itiwillrbeffappaiientrfthat" the.presentinventionzcontemplatesa spring'type 25;

fastenerf` offextremely z simple.- and practical; con-sA struction: The I.sh-seta metal; insert: may be rproducedifromi a zsin'gle'-1ziiecevoffsheet4v metal stock,

andlaa'ssplit rin'gmaybe mount'edupom the',t innen periphery ofxltlreentering-end"offtheislfiank;V TheL 30.?,

splitring-zprnvides'ia positive or. rmabutmenti fori the? screwathreads; :and thus insures Afunifnrm expansion; of f. tlreenteringendi of-.ztheinsert, f.

Whileifor.purpesesfofllustratiomarrinsert,has

beenfdisclesedv designed speeicallyifiorfaccomfy 35i modating afcoars'esptclr screwthread; it willbe; appanentzthat'; rnorilcations: or'; changes togaQ-v commodatesscrew :threads of varyingzfpitchfmay beifrnade" withoutrdepantingj.:fromthe: spirit and:

scnpefof l.th'epresent invention; 40:

Tlieiinvention is:` hereby.; claimed asnfollowfs:l

1. :Atworpieoascrew accommodatingaexpansion z insertof sheetnmetalxhaving: a-A hollow -ishankpor `y` tion, a head structure at one;,extremitythereef,

annexpansiblelsectiorrrat the; oppositeextremity. 45:

and aisplit metallic rin'glmemben mounted orr'and;V supportedabyathefexpansiblerportica :fi the'shal'1k;V

v'accordaiiee wizthf-,claim 1, wherein the hollow shank portion presents a periphery which is polygonalgriicrossfgsection.

3. A.screw accommodating expansion insert in accordance with claim 1, wherein the means for operatively coacting with thread helices of a complemental screwiconsistsof struck; .ontsportionsl -of'thefshank stockfcircumierentially spaced and A -inhelicali alignment', r

4 A screw-'1 accommodatingi expansion inserti-inf; accordance with' claim f1', wherein Lthe'rngxmemr--l ber is mounted by inwardly bentzloortions:onfsaidrl` shank-'consistingrof a 1pluralityof lcireun'iferentiallyI disposedi independently. flexibleztabszw.

EDMOND 6.1 CROW'IHIE1P.=,=lv

REFERENGESJGITED f The following references are voi record in@ the:` le of thisr patent?y UNITED STATES PATENTS Number Name 1 Date 1,095,366 Abbott' May ,5,19'14 1,169,695" SWedlufldr ,Jah;f25, '-1916 1,203,546" Parsons Oct.'31,1916 1,342,738 Burke June 8,1920L 1,784,755. Rosenberg Dec'.9,"1930f 1,940,413" Gray Dec: 19,' 1933',E

FGREIGN; PATENTS Numberv Country2 Datel:

7,8913' Austria; Feb.''1,51902 

